Strut elements, by which various components or assemblies are connected to one another, are known from the prior art. These can be fixed struts such as frame struts or base supports, which are arranged essentially unmovably between components and thereby prevent relative movement of the components in relation to one another.
Also known from the prior art are movable strut elements such as coupling struts, hinged supports, chassis struts and steering or track rods, which in most cases are connected movably or articulated to the corresponding components or assemblies to be joined, for example in order to couple the joined components to one another with a degree of freedom of movement, or in order to control the position or the angular position of assemblies—such as wheel carriers on a motor vehicle.
Particularly in vehicle engineering severe demands are made on such strut elements, including in particular load-bearing capacity and fatigue strength, high security against failure and good corrosion resistance. At the same time such strut elements should take up as little space as possible in order to, as much as possible, avoid colliding with adjacent assemblies and so as not to restrict the freedom of movement of other components and assemblies, particularly in the chassis area. A general requirement for such strut elements is usually also length adjustability, which is usually achieved by making the strut in two parts with a threaded joint between them.
From the prior art steering and track rods, or in general strut elements are known, in which a usually tubular strut has an internal thread at one or both ends, which serves to receive a threaded bolt. In turn, the threaded bolt can be connected to components to be joined, for example to the ball head of a ball joint. To set the desired length of the strut element, for example to be able to adjust the wheel geometry or the steering angle in the motor vehicle, the threaded bolt is screwed into the thread of the tubular strut until the desired strut length is produced. To prevent play or autonomous displacement of the strut element, it is then necessary to fix the threaded bolt in the internal thread of the strut firmly and without any play.
In the prior art, this requirement is usually fulfilled by providing an axial slot in the end area of the strut that has the internal thread, and at the same time arranging on the outside of the strut in the area of the internal thread or the axial slot of the strut a clamping collar. By tightening the clamping collar/with the threaded bolt screwed in to the desired depth the strut, in the area of its internal thread, is compressed radially so that it firmly clamps the threaded bolt.
However, this method known from the prior art for fixing the threaded bolt of a strut element in the desired axial position has disadvantages. Thus, the necessary axial slotting of the threaded zone of the strut is, first of all, associated with considerable weakening of the end of the strut in relation to torsion, bending and buckling resistance. Furthermore, by virtue of the axial slot in the threaded zone, surfaces are created that are prone to corrosion, in that water or other corrosive media can make their way into the thread of the strut or the threaded bolt, or even penetrate to the inside of the strut. This can result in further weakening of the strut, or the internal strut thread and the threaded bolt can bind together due to corrosion, which can make it more difficult, later, to adjust or dismantle the strut element.
Moreover, the clamping collar needed for compressed the end of the strut in the threaded zone usually takes up considerable installation space, whereby the space required by the strut element in this area is often almost doubled. This can result in contact with adjacent components or assemblies, particularly since the angular position of the clamping collar in the threaded zone of the strut is usually not exactly defined or fixed. In principle, therefore, the clamping collar can extend out from the strut in any direction, and in turn this has to be taken into account during the design and interference checking of the surrounding package of assemblies.
Finally, for the secure and correct assembly of such struts it is usually necessary to provide an all-round annular groove on the end of the strut in the threaded area, so as to ensure a defined axial position of the clamping collar when it is fitted. The formation of both the axial slot and the annular groove not only weaken the end of the strut, but also require additional working steps for their production, and therefore incur corresponding machining costs.